Magnesium alloy



Nov. 15, 1927. 1,649,521

J. A. GANN MAGNESIUM ALLOY Filed 001'.. 27, 1921 ATTORNEYS' Patented Nov. 15', 1927.

UNITED STATES 1,649,521 PATENT OFFICE.

JOHN A. GANN, OF MIDLAND, MICHIGAN, ASSIGNOR T THE DOW CHEMICAL COM- PANY, OF MIDLAND, MICHIGAN, A CORPORATION 0F MICHIGAN.

MAGNESIUM ALLOY.

Application led October 27, ,11921. Serial No. 510,796.

The present improved alloy is one in which magnesium is the predominant element, the object bein to develop analloy that will possess the c aracteristic lightness which is obtained by the use of magnesium in excess of 80 per cent, while such alloy will be characterized by high tensile strength and hardness, coupled with moderate brittleness, as well as have a high melting point and high thermal conductivity.

The field of use in the mechanical arts to which an alloy possessing the lightness and physical characteristics enumerated above may be applied is extensive and need not be described in detail for the purpose in hand. Where it is desired to increase the hardness and/or at the same time reduce the brittleness of the alloy, the character of the latter may be modified by adding one or more other metals in varying quantities, as will be hereinafter explained, the present invention consisting of an alloy of magnesium and nickel with or without the addition of such further metals together with the steps involved in the making of such alloy hereinafter fully described and particularly pointed out in the claims. The annexed drawing and the following description it will be understood set forth several of the various ways in which the principle of the invention may be carried out.

In said annexed drawing The single figure there appearing is a diagrammatic representation of certain physical properties discovered in a binary magnesium-nickel alloy of the class in hand.

In said diagrammatic drawing the physical properties represented, it will be noted, are the impact-toughness, hardness and tensile strengthv of the alloy, the hardness being determined by the Brinell method and scaled to correspond with the impact-toughness, the latter being-determined by the singleblow method. While such impact-toughness i drops quite rapidly with the addition of nickel, as will be seen, the curve indicating this property becomes more nearly horizontal at higher percentages of added metal. The tensile strength on the contrary increases rapidly at first, then more slowly and finally begins to fall oli", while the Brinell hardness beginning with an alloy containing a little over 1 per cent of nickel increases rapidly with the addition of further nickel throughout the range shown on the diagram.

Yternary alloy usin In order to secure a proper balance in respect to the characteristics in question I prefer to employ between 5 per cent and 8 per cent of nickel, castings made from such resulting alloy having a specific gravity of from 1.80 to 1.90; tensile strength from 18.000 to 19.000 per square inch; Brinell hardness from 45 to 50; and single-blow impact-toughness from 4.0 to 30.

As previously indicated, where it is desired to modify the characteristic of hardness and particularly the brittlen'ess which is associated therewith in the case of the binary alloy under consideration, I have found that the laddition of a small proportion of aluminum, or of aluminum and zinc, is advantageous. A satisfactory formula for a my im roved binary magnesium-nickel a oy as a lows, viz, magnesium 90 per cent; nickel l6 per cent; and aluminum 4 per cent. Where in addition to aluminum zinc is added as an ingredient, the following formula has been found to give satisfactory results; magne-4 sium 90 per cent; nickel 5 per cent; aluminum 3 per cent; and zinc 2 per cent.

Even when the amount of aluminum added is relatively` larger than that of nickel, the characteristic effects of the latter ingredient are retained to a noticeable degree, as for example in the following ternary alloy, viz; magnesium 90 per cent,- aluminum 8 per cent, and nickel 2 per cent.

- To make my improved alloy, a measured quantity of pure magnesium metal is first melted in a suitable pot along with the proper amount of a fiux that while heavier than such metal will have proper surface tension to promptly and effectively coat the metal. As an example of such a iux, approximately equal parts of anhydrous magnesium chloride and sodium chloride may ase is as folbe employed and if the specific gravity of the resultant mixture proves inadequate to float the metal after it has been alloyed, a small amount of bariumchloride may be.- added. A relatively small portion of the kmolten magnesium metal is then taken upin a ladle and the whole or part of the nickel, depending upon the total percentage thereof to be added to the batch, is rst placed in such ladle and melted with themagnesium therein, thereby producing. an alloy very high in nickel. In order .to insure the interfusing of the nickel with the loo magnesium, it is necessary that it be in finely divided form such as wire, or else it mayV be powdered before being added. The contents of the ladle are then gradually added.

to the main body of molten magnesium with the result that the nickel will diffuse throughout the mass and not drop through into the body of iiux in which the latter floats and so be lost.` As soon as the introduction of theA nickel alloy has been effected,

the whole mass is vwell puddled and the operation may then be regarded as complete and the molten alloy cast either into in ots or directly into the form of the mechamcal parts for which it is intended to be used.

2o of such additional metal or metals ma the main body of the molten \magnesi`um metal, resulting in the production of an alloy in which such' magnesium is the predominant ingredient, while of the other ingredients the nickel is relativ/ely the larger 1n amount. In some cases, moreover, when '35 tively more than one metal is to be added to the.

magnesium such metals may be first coml bined togct er and added in the form of the resulting alloy, which may contain a relalow percentage of magnesium if desired. a

For convenience in defining the relative proportions of the metals that enter into the alloy, the magnesium may be referred to as present in predominant amount, meaning an amount on the order of 80 per cent or more -of the total; While inf referring to the resence of other constituents in substantial) but relatively small amounts, it will be understood that amounts are meant on the order of those specified in the formulas hereinbefore set forth, due regard being givento the fact that the total of such other ingredients will decrease as the amount of the predominant constituent is increased.

Other modes of applying the principle of my invention may be employed instead of the one explained, change beingl made as vregards the ste s herein disclosed or the ingredients emp oyed lin carrying out such steps, provided the steps or ingredients set forth in the following claims or the equivalent of such steps or ingredients be employed. y

l. therefore particularly point out and distinctly claim as my invention u 1. As a new product, an alloy containing magnesium and nickel, wherein the magnesium largely predominates, said alloy having a tensilestrength in excess of 18,000

pounds per square inch, Brinell hardness approximately 45 and single-blow impacttoughness between 40 and 30.

2. As a new roduct, an alloy containing not less than eighty nor more than ninetynine and one-half per cent of magnesium and not more than twenty nor less than one-half of one per cent of nickel, said alloy having a tensile strength in excess of 18,000 pounds 'per square inch, Brinell hardness approximately 45 and single-blow impacttoughness between 40 and 30.

3. As a new product, an alloy containing from ninety to ninety-four per cent of magnesium and from six to eight per cent of nickel, said alloy having a tensile strength in excess of 18,000 pounds per square inch, Brinell hardness approximately 45 and single-blow impact-toughness between 40 and 30.

4. As a new roduct, an alloy containing magnesium, nic el and aluminum, wherein the magnesium largely predominates and the remaining constituents are present in substantial but relatively small amounts.

5. As a newl product, an alloy containing magnesium, nickel andK aluminum, wherein the magnesium largely predominates and the remaining constituents are present in substantial but `relatively small amounts, the nickel being in excess of the aluminum.

6. As a new product, an alloy containing magnesium, nickel, aluminum and zinc, wherein the magnesium largely predominates andthe remaining constituents are present lin substantial but relatively small amounts, the nickel being in excess of the aluminum and the amount of the' latter be ing approximately the same as that -of the zinc. f7. As a new product, an alloy containing magnesium, nickel, aluminum and zinc,

Vwherein the magnesium largely predominates and the remaining4 constituents are present in substantial but relatively small amounts, the nickel being in excess of the aluminum and the amount of the latter being slightly greater than that ofthe zinc.

8. As a new product, an alloy containing not less than eighty nor more than ninetynine and one-half per cent of magnesium not more than twenty nor less than one-half of one per cent of nickel, and aluminum in substantial but relatively small proportion.

9. As a new product, an alloy containing not less than elghty nor more than ninetynine and one-half per cent of magnesium not more than twenty nor less than one-half of one per cent of nickel, and aluminum and zinc in substantial but relatively small proportions.

10. As a new product, an alloy containing approximately the indicated percentages of the following metals viz z-magnesium ninety per cent, nickel ve per cent, aluminum three per cent and zinc two per cent.

11. The method of making a magnesiumnickel alloy, which consists in first interfusing the desired amount of nickel with a relatively smell quantity of the total magnesium in such alloy, and then adding the resulting alloy to the remaining quantity of magnesium in molten state.

12. The method of making e magnesiumnickel alloy, wherein the magnesium largely 'is produced, and then adding such resulting alloy to the remaining quantity of magnesium.

Signed by me this 24th day of October,

JOHN A. GANN. 

